Download L1 - Amines

Amines
Amines
Amines are derivatives of ammonia,
NH3, where one or more hydrogens have
been replaced by an organic (R) group.
The Nitrogen
Containing
Organic
Molecules
Naming Primary Amines
When only one hydrogen has been
replaced by an –R group, the –NH2 group
is treated as a substituent called the
amino group.
Therefore, we treat the –R group as the
parent chain and name accordingly.
Examples:
Naming Secondary and Tertiary Amines
:
When multiple hydrogens have been
replaced by –R groups, the –R groups are
treated a substituents.
To name 2o, or 3o amines, list the alkyl
substituents in alphabetical order
(including di, tri, etc…) followed by the
word amine
Examples:
:
N
H–N
Diethyl amine
Naming Aromatic Amines
Aniline is the simplest aromatic amine.
Compounds are named as substituted
anilines.
An italic “N” is used to indicate that an
alkyl group is attached to the nitrogen
and not to the ring.
Examples:
You are not
responsible for
naming aromatic
amines
sec-butyl-di-iso-propyl amine
Physical Properties of Amines
• Organic bases.
• Generally have strong,
unpleasant odors.
• Are found extensively in
biological systems.
• Found in both controlled
and medicinal
compounds
1,5 - diaminopentane
H2N – CH2-CH2-CH2-CH2-CH2 – NH2
Cadaverine
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Effects of hydrogen
bonding in primary
alcohols vs. primary
amines
Physical Properties, cont.
Primary and secondary amines can form
hydrogen bonds between molecules.
The N-H bond is not quite as polar as
the O-H bond.
The hydrogen bonds are not as strong
as those of alcohols, so amine boiling
points are somewhat lower than those of
alcohols.
Physical Properties, cont.
Amines can hydrogen bond with water,
making smaller amine molecules usually
water soluble.
Basicity of Amines
Amines behave as weak bases in water
(similar to ammonia) producing
substituted ammonium ions.
R-NH2 + H2O ⇔ R-NH3+ + OH-
Secondary and tertiary amines behave in
a similar manner.
Biologically Important Amines
Amine Neurotransmitter – a chemical
bridge between nerve cells.
Important Amine Neurotransmitters
•Acetylcholine
•Dopamine – synthesized from
the amino acid tyrosine.
•Norepinephrine – synthesized
from dopamine, may be
associated with mental illness.
•Serotonin – synthesized from
the amino acid tryptophan, may
be associated with mental
illness.
Other Biologically Important Amines
Epinephrine (adrenaline) – more
important as a hormone than a
neurotransmitter. Fight-or-flight
hormone, released in response to pain,
anger, or fear, increases blood glucose
level for energy.
Amphetamines – nervous system
stimulants, similar in structure to
epinephrine. Abuse of amphetamines
has severe detrimental effects on the
body and the mind.
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Other Biologically Important Amines
Alkaloids – a class of nitrogen–
containing organic compounds obtained
from plants.
Amine Reactions
Neutralization
Neutralization – (Addition) All
amines behave as weak bases and form
salts when they react with acids such as
HCl.
Examples include:
•Nicotine – found in tobacco
•Caffeine – found in coffee and cola drinks
•Quinine – used to treat malaria
•Opium – used to make codeine (in cough
medicines), morphine (pain killer) and
heroin.
Amine Reactions, cont.
Amine
Amine Esterification –
(Substitution) Amines react with carboxylic
acids, acid chlorides or acid anhydrides to
form amides.
Primary and secondary amines can form
amides.
Tertiary amines do not react to form amides.
: :
=O
=O
: :
R-NH2 + HCl → R-NH3+Clamine acid amine salt
Examples:
H- :
:
H-
: :
R – C – O – H + H – N – R → R – C – N – R + H2O
1. Write an equation for the reaction
of ethyl methyl amine with methanoic
acid, methanoic chloride ( CH3-COCl),
and methanoic anhydride.
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